Medication adherence remains one of the most persistent challenges in glaucoma management. Cost, complex regimens, forgetfulness, cognitive decline, and difficulty with drop instillation can all interfere with consistent treatment.1 Lower adherence to topical ocular hypotensive therapy has been associated with faster visual field progression.2,3 Chronic topical exposure can also contribute to ocular surface disease.4 For some patients, particularly those using multiple medications preserved with benzalkonium chloride (BAK), treatment-related ocular surface disease can become debilitating and difficult to manage.4 Although preservative-free formulations may improve tolerability, cost and insurance coverage often limit access.
Physician-administered sustained drug delivery offers a different model. The approval of Durysta (AbbVie), a bimatoprost intracameral implant, and iDose TR (Glaukos), a travoprost intracameral implant, established that glaucoma therapy can be delivered continuously without relying on daily patient administration.5,6
The investigational pipeline is now confronting a more difficult problem: how to extend treatment and repeat it safely to manage a lifelong disease. Developers are pursuing several approaches, including expanding the capacity of permanent reservoirs, biodegradable implants, and drug delivery incorporated into cataract surgery. Each approach has implications for treatment duration, approval for repeated dosing, safety monitoring, and patient selection.
Expanding a Familiar Reservoir
The FDA-approved iDose TR demonstrated sustained IOP reduction and favorable corneal endothelial safety through 36 months in phase 2b and 3 studies.7 The iDose Trex retains the same basic design, while incorporating nearly twice the drug capacity; it is currently being evaluated in a phase 2b/3 clinical program.8 Early clinical experience with iDose Trex, presented at the 2026 American Glaucoma Society meeting in Washington, DC, demonstrated substantial IOP reduction through 6 weeks in the first 10 patients treated, although longer-term efficacy and safety data have not yet been published.9
Because iDose Trex builds on an established platform, its potential place in practice is relatively easy to envision. The permanent design, however, requires adequate angle anatomy and visualization, and exchanging an anchored device is more involved than repeating an injection. The central question is whether greater capacity will translate into meaningfully longer treatment without compromising implant stability or endothelial safety.
Biodegradable Implants
Other developers are pursuing biodegradable intracameral platforms designed to simplify retreatment after the device has completely degraded. Australian company PolyActiva is developing PA5108, a microimplant that delivers latanoprost free acid, the pharmacologically active metabolite, using the company’s Prezia polymer platform. The implant is designed to provide a consistent rate of drug release and then biodegrade completely, allowing repeat implantation without leaving permanent material in the anterior chamber.1,10
In 2024 the company reported phase 2a findings showing IOP reductions of more than 20% from baseline in each of 2 consecutive 21-week treatment cycles. In a small repeat-dose cohort, PolyActiva reported no adverse effect on the corneal endothelium through 48 weeks of monitoring.11 A US phase 2b study is evaluating 80-μg and 160-μg doses, including repeat administration at 6 months, vs topical latanoprost.12 If earlier findings are confirmed in a larger population, PA5108 could address a key limitation of first-generation intracameral therapy.
OTX-TIC (Paxtrava; Ocular Therapeutix) is an injectable implant that uses the company’s Elutyx hydrogel technology to deliver travoprost. Company-reported data from the phase 2 trial for the 26-μg implant showed mean IOP reductions of approximately 24% to 30% through 6 months following a single administration. Ocular Therapeutix also reported consistent implant biodegradation and no observed effect on the corneal endothelium at 6 months.13 A small repeat-dose substudy was subsequently initiated. In contrast to an anchored reservoir, this approach pairs injection-based administration with eventual biodegradation.
Most evidence for these biodegradable platforms comes from small studies, conference presentations, or company disclosures. Larger controlled trials and outcomes across multiple treatment cycles will be necessary to define their clinical roles.10
Incorporating Drug Delivery Into Cataract Surgery
SpyGlass Pharma’s bimatoprost drug pad–intraocular lens (BIM-IOL) system takes a different approach by incorporating nonbioerodible, drug-eluting pads at the optic-haptic junction of a monofocal IOL. The system is intended to deliver bimatoprost continuously for up to 3 years after routine cataract surgery without a separate implant.
In a combined phase 1/2 study, 12-month top-line results at the intended 78-μg dose showed a 34% mean IOP reduction and freedom from topical IOP-lowering drops in 98% of participants.14,15 In January 2026, the company began enrolling a pair of phase 3 trials, Rhine and Rhone. Each study will compare the BIM-IOL System with a standard commercial IOL combined with twice-daily topical timolol. Co-primary endpoints include time-matched change in mean IOP from baseline and the proportion of patients achieving best-corrected distance visual acuity of 20/40 or better. Participants will be followed for up to 36 months to assess long-term safety, efficacy, and durability.16,17
Incorporating sustained therapy into an already indicated procedure is an attractive clinical model. Because the system is implanted during cataract surgery, however, it would not be available to patients who are already pseudophakic. Long-term evaluation must also account for both drug delivery and optical performance.
The Farther Horizon
Other approaches remain earlier in development. Glaukos lists GLK-311, an extraocular sustained-release formulation based on its iLution platform, in phase 2 trials, although the drug payload and publicly available clinical data are limited.10 Subconjunctival hydrogels, punctal systems, nanoparticle formulations, and smart contact lenses are also under investigation.1,10
Although these platforms may avoid an intraocular procedure, those that deliver medication across the ocular surface may not eliminate the tolerability problems associated with chronic topical exposure. For now, these technologies are best viewed as signals of where the field may eventually move rather than near-term additions to practice.
Factors That Will Affect Clinical Adoption
Defining Meaningful Durability
“Duration” can describe several different outcomes: the length of time an implant remains in the anterior chamber, drug-eluting time, how long IOP remains below baseline, or how long an eye avoids additional treatment. These measures are not interchangeable. For clinicians, a predictable 6-month treatment interval may be more useful than a longer but highly variable residual effect. Future studies should therefore report the proportion of eyes remaining free of additional medication or retreatment and the consistency of IOP control across the dosing interval, not only the mean change from baseline at selected visits.
Comparisons across programs also require caution because trials use different baseline IOP requirements, controls, rescue criteria, and efficacy time points. The most clinically informative data will come from repeated treatment cycles using a clearly defined retreatment strategy. That is when these platforms will begin to show whether sustained delivery can function as longitudinal glaucoma therapy rather than a temporary reduction in medication burden.
Safety Across the Treatment Cycle
Current products demonstrate why retreatment requires careful consideration. Because of the risk of corneal endothelial cell loss, the Durysta label limits treatment to one implant per eye without retreatment.6 In the ARTEMIS trials, repeat administrations at fixed 16-week intervals were associated with ≥20% corneal endothelial cell density (CECD) loss in approximately 10% of eyes receiving the 10-μg implant.18 By comparison, the TRITON phase 3b study evaluated as-needed retreatment and reported a mean CECD change of -4.3% at 12 months after a single implant and a -8.5% after a second implant.19 These findings illustrate how retreatment interval and cumulative exposure may influence safety.
The January 2026 iDose TR label provides a different model. Readministration involves placing a new device and removing the previous implant. It is not recommended more than once per year, and specular microscopy is required before initial implantation and each readministration. Treatment should be withheld when central endothelial cell loss reaches specified thresholds.5
Biodegradable platforms avoid permanent hardware accumulation, but biodegradation alone does not establish repeatability. Corneal endothelial health remains the principal concern, alongside implant position, migration, intraocular inflammation, and the procedural risks of injection or exchange. For clinicians, the most informative studies will report endothelial cell density, implant position, inflammatory events, and outcomes across multiple treatment cycles.10
Matching the Platform to the Patient
Sustained delivery is unlikely to follow a one-size-fits-all algorithm. A patient with significant ocular surface disease may benefit from reducing chronic topical exposure. A patient with limited dexterity, cognitive impairment, an unpredictable schedule, or limited caregiver support may benefit from transferring more treatment responsibility from the patient to the physician.
Other patients may prefer selective laser trabeculoplasty (SLT) or a combined cataract and minimally invasive glaucoma surgery (MIGS) procedure. Sustained delivery should be viewed as complementary rather than universally competitive with other IOP-lowering strategies. It could provide an intermediate option when SLT offers inadequate control but incisional treatment is not yet warranted, or reduce residual medication burden after SLT or MIGS. Angle anatomy, lens status, endothelial reserve, and target IOP will help determine which platform, if any, is appropriate.
Workflow and Access
Clinical performance will not guarantee adoption. Acquisition cost, payer coverage, procedural reimbursement, follow-up testing, and retreatment intervals will determine whether these technologies are practical in routine care. Specular microscopy and implant exchange add workflow requirements, whereas injectable biodegradable products may offer simpler retreatment if their safety is confirmed. Evolving Medicare coverage and proposed Local Coverage Determinations may further affect patient access, reimplantation, and practice workflow.
Conclusion
The next generation of physician-administered sustained delivery is not pursuing a single solution. Current development programs are testing longer-lasting reservoirs, complete biodegradation, injectable hydrogel depots, and integration with cataract surgery. The platforms that reach practice will need to demonstrate sustained IOP reduction, acceptable corneal endothelial safety, and practical retreatment approaches. Their ultimate value will depend on matching the delivery strategy to each patient’s anatomy, treatment burden, and preferences. GP
References
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2. Shu YH, Wu J, Luong T, et al. Topical medication adherence and visual field progression in open-angle glaucoma: analysis of a large US health care system. J Glaucoma. 2021;30(12):1047-1055. doi:10.1097/IJG.0000000000001943
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8. Glaukos announces positive clinical updates for its iDose sustained-release procedural pharmaceutical platform. January 14, 2025. Accessed August 6, 2026. https://investors.glaukos.com/news/news-details/2025/Glaukos-Announces-Positive-Clinical-Updates-for-its-iDose-Sustained-Release-Procedural-Pharmaceutical-Platform
9. Sarkisian SR Jr. Early iDose TREX data show double-digit IOP reduction. Glaucoma Physician. February 20, 2026. Accessed August 6, 2026. https://www.glaucomaphysician.net/issues/2026/march/ags24/
10. Shi KSY, Abubaker Y, Lang MV, et al. Overview of intracameral drug delivery systems in glaucoma. Clin Ophthalmol. 2026;20:568183. doi:10.2147/OPTH.S568183
11. PolyActiva showcases promising clinical data highlighting its polymer technology’s potential to transform glaucoma care. Press release. October 30, 2024. Accessed August 6, 2026.https://polyactiva.com/wp-content/uploads/2024/10/PolyActiva-Eyecelerator-Press-Release_FINAL.pdf
12. Evaluate efficacy and safety of PA5108 ocular implants in primary open angle glaucoma or ocular hypertension. ClinicalTrials.gov identifier: NCT06964191. Updated July 8, 2026. Accessed August 6, 2026. https://clinicaltrials.gov/study/NCT06964191
13. Ocular Therapeutix announces positive phase 2 Paxtrava glaucoma data at the American Society of Cataract and Refractive Surgery 2024 annual meeting. Press release. April 6, 2024. Accessed August 6, 2026. https://investors.ocutx.com/node/12661/pdf
14. Tan NE, Katz G, Robles M, et al. Prospective pilot study of sustained release bimatoprost implant with SpyGlass intraocular lens: 3-year results. Ophthalmol Ther. 2026;15(2):855-874. doi:10.1007/s40123-026-01313-4.
15. SpyGlass reports 12-month results for BIM-IOL system. Glaucoma Physician. March 10, 2026. Accessed August 6, 2026. https://www.glaucomaphysician.net/news/2026/spyglass-reports-12-month-results-for-bim-iol-system/
16. Evaluation of the safety and efficacy of the bimatoprost implant system used in combination with the SpyGlass IOL compared to timolol ophthalmic solution (Rhine). ClinicalTrials.gov identifier: NCT07218783. Updated October 20, 2025. Accessed August 6, 2026. https://clinicaltrials.gov/study/NCT07218783
17. Evaluation of the safety and efficacy of the bimatoprost implant system used in combination with the SpyGlass IOL compared to timolol ophthalmic solution (Rhone). ClinicalTrials.gov identifier: NCT07218796. Updated October 20, 2025. Accessed August 6, 2026. https://clinicaltrials.gov/study/NCT07218796
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19. Silverstein SM, Oddone F, Kolko M, et al. Safety and longevity of intraocular pressure control after bimatoprost implant administration: interim analysis of a phase 3b clinical trial (TRITON). Drugs. 2025;85(4):557-570. doi:10.1007/s40265-025-02154-4